Insulation shield for electric wiring



n- 1930- E. J. SCHNEIDER TAL I, 1,742,438

INSULATION SHIELD FOR ELECTRIC WIRING Filed March 21, 1929 BY Merritt 5.Brad i.

ATTOR EY Patented Jan. 7, 1930 ,umren STATES PATENT OFF/ICE EDWIN J.SCHNEIDER, 0E JAMAICA, am) MERRITT B. BRADT, or BROOKLYN, NEWYOBKMASSIGNOBS To EASTERN TUBE AND Toor. co. 1nd, oE'BnooxLYN, NEW YORK,

A CORPORATION OF NEW YORK rnsptn'rroiv SHIELD FOR ELEoTEIc WIRINGvarious kinds and classes and especially where two ormore wires arearranged in and passed through a .metallicouter casing or jacket of anykind'or class and particularly to the'provision of a shield ofinsulating material adapted to be arranged within an end portionot thecasing and betweenit and the wires contained therein to protect saidwires and shield them from coming in contact with sharp edgesot saidcasing; and the object of the invention is to provide a shield of theclass and for the purpose specified, the main body portion of which isshield-like in form. and comprises an arc-shapedwa'll, opposite sideedges of which are curved and tapered to form a pointed or prong-likeend and the other end of the-shield extending in the form ot a splittube forming a finger piece and'insulating collar; a further objectbeing to provide adjacent the last named or collar end of the shield, anannular outwardly projecting member which forms a stop and flangeadapted to overlie the edge of the metallic casing, said enlargedportion being preferably tapered at its free end to operate as a wedgeto securely retain the shield in position and toplace the wires underslight compression withinthe outer casing and toexpand said outer casingwhen composed of the flexible type; a further object being to providethe inner or prong end portion of the shield with .40 V proof andtofacilitate the operation .of applying the same and with these andother an outwardly pressed portion adapted to engage one of the coils ofa flexible metallic casingto aid in securing the shield againstdisplacement a still furtherobject being to provide ashield of the classdescribed which is composed [of inexpensive .material, and" which ispreferably coated with a greasyor wax-like element to render the samemoisture objects in view, the invention consists in an hereinafterdescribed and claimed.

insulator of the class andior the purpose. specified, which is simple inconstruction efficient in use," and which is constructed-asThe'invention is fullydisclOsed' in the following specification, ofwhich theaccompanying drawing forms a part, in which the sep:

Application filed March 21,

1929. Serial no. 348,744.

arate parts of our improvement are designated. by suitable referencecharacters in each of the views, and in which Fig. l i's a diagrammatic,sectional View, illustrating one method of arranging a shield madeaccording to the invention, within a metallic casing and between it andthe wires contained therein.

Fig. 2 is a section on the line 22 of Fig. 1.

Fig. 3 is a face View of the shield shown in Fig. 1, detached.

Fig. 4 is a side vi in Fig. 3.

Fig. 5 is a longitudinal, sectional view through a shield showing aslight modification.

Fig. 6 is a view similar to another modification, and,

Fig. 7 is a view similar to Fig. 1 showing another modification.

In Figs. 1 and 2 of the drawing, a conductor or cable of the flexiblearmored type is shown to illustrate one use of the invention.

ew of the shield shown In these figures, 10 represents a flexible me- 75tallic casing fashioned from-a spirally wound strip of metal 10 the sideedges of which are fashioned to interlock adjacent windings as inconventional casings of this class, and this Fig. 5 showing structureforms spiral recesses 11 on the inner surface of the casing. Itwill beunderstood at this time that the outer metal casing may be of anydesired form and construction and may constitute a metal tube. Arrangedin the casing 10 are two or more in- ,sulated conductors, two of whichare shown in the accompanying drawing and are designated bytheireference numerals 12 and 13.

These conductors may be of any desired con sulating material of any kindor class such for example as fibre, .bakelite,*hard*rubber,'

paper board and so forth, one end portion of the shield being fashionedto'form a pointed 5 i .or pronged end15,the side walls 16 of which arecurved and tapered in the manner shown from the pointed end 15 to thepoint 17 where the shield is substantially cylindrical in form, beingsplit longitudinally of its wall to permit the expansion and contractionof the shield in the operation of inserting it into the casing 10.

'Outwardly of the point 17 the shield is provided with an annular body18, the inner wall 18 of which tapers gradually onto the cylindricalwall and the outer wall 18 of which is similarly tapered, the latterbeing more abrupt however; and the wall 18 terminates in a straightcylindrical and projecting collar 19 which serves as a finger piece andas an insulating collar adapted to be arranged within an aperture in afixture casing or other body part 20 which is partially illustrated inFig. 1 of the drawing, so as to insulate the conductors 12 and 13 whereit passes into and through the body 20. It is also preferred that thepointed end portion of the shield be provided with an outwardly pressedhead 21 arranged substantially centrally of said pronged end portion andat a point opposite the split side of the shield to form a retainingmemberof said bead which will operate in the recesses 11 of one of thecoils to aid in holding the shield against displacement.

In armored conductors of the class referred to, the arrangement of theconductors 12 and 13 within the casing 10 forms at opposite sides of thecasing and therewithin, valleys or spaces designated by the referencenumeral 22, note Fig. 2. In the use of the shield, the pointed orpronged end 15 thereof is inserted into the casing by placing said endin one of the recesses 22. As the prong is pressed into the casing 10and around the conductors 12 and,18, the curved and beveled walls 16 ofthe shield operate to feed and guide the shield in its inward movement,offering no resistance in this operation except that the bead 21 willestablish a slight resistance in passing over the inwardly projectingportions arranged between the recesses 11.

In completing the inward movement of the shield, the beveled wall 18 ofthe annular. body 18 will operate to firmly compress the conductors 12and 13 and further to expand the casing 10, especially when this casingis constructed of the flexible type.

casing is employed, the result will be simply to compress and firmlyretain the conductors in position and also to support the shield.'

It will be understood. that the collar 19 will extend beyond the freeend of the casing, and the body 18 serves as a shield or guard, arrangedat the free edge of the casing in spaced relation with reference to theconductors b virtue of the air chamber'forined' within thebead'outwardly of the conductors.

In Fig. 5 of the drawing, we have shown a Figs. 1 to 4 inclusive. Inthis figure,.the reference characters 15, 16, 17 19 and 21 will figures,will not take If a rigid y ment fromthecnd of the designate like parts,and substituted for the head 18 is a bead 23, differing from the bead 18in that one wall 23 tapers gradually onto the wall of the pronged end upto the point 17,

pass freely into the casing of a cable or to allow the same to extendintotherecess 11 to retain the shield against accidental displacement.

In this construction, we have substituted for the annular beads 18 and23 shown in the other figures, an annular head 26 which is more in theform of a flange and is fashioned by pressing the wall of the shieldoutwardly to form a flange of two-ply thickness which is adapted to buttagainst the outer edge of the casing 10 in the use of the shield. Inother words, the beveled wall and wedge-like action accomplished therebyas in the other place in this structure, it being understood, however,that the placement of the shield in the casing and around theconductors, which normally fits snugly in the casing, is sufiicient toplace the conductors under slight compression, but the degree ofoperationwill not be as great as in the use of the tapered wallstructure shown in Figs; 1 to 5 inclusive. The shield shown in Fig. 6also includes an outwardly projecting collar 27 which forms theresulting collar and finger piece as in the other structures.

In Fig. 7 of the drawing, we have shown another modification wherein aferrule 28 of conventional form is employed in conjunction with a shieldmade according to the several disclosures, the shield shown in Figs. 1to e inclusive being preferably employed, and like references willdesignate like parts with respect to said shield, which is designated at14;, and consists of the pronged end 15, tapered wall 16, the outwardlyproj ecting member or bead 18 and the collar 19.

The ferrule 28 is of a type having a screw threaded end portion 29adapted to engage the spirally arranged strips 10 in the manner ofscrewing a nut upon a thread. The

projecting member 18 of the shield 14 is preferably arranged in aposition to meet the threads 39 of' the ferrule so as to provide meansfor locking the shield against displaceouter end of the ferrule has aninwardly turned flange 30 engaging the enlargement or member 18 toaccomplish this result. It will casing 10. The

also be noted that the projecting collar serves to insulate conductors12 and 13. g It is customary to employ metallic ferrules, and

while this type of ferrule, may be employed, it will also be understoodthat non-metallic devices of this class may be used. It is alsopreferred that the outer surfaces of the ferrule be roughened or nurledto facilitate the attachment of the ferrule.

In the use of the device, the shield 14 is first placed in positionbetween the conductors and the casmg, after which the ferrule is appliedand threaded upon the shield and dling the same, and will alsofacilitate the insertion of the cable into the knock out openings ofterminal boxes of various kinds and classes.

It will be understood that while we have shown afew forms of shields forcarrying our invention into effect, andhave illustrated one particularuse thereof, that our invention is not necessarily limited to thespecific details of construction herein shown and described, nor to theuses herein set, out, and various otherchanges in and modifications ofthe structure herein disclosed may be made within the scope of theappended claims without departing from the spirit-of our invention orsacrificing its advantages.

Having fully described our invention, what we claim asnew and desire tosecure by Letters Patent, is p s l. The combination withinsulatedelectric conductors arranged in an outer metallic cas} ing, of a shieldcomposed ofinsulating material adapted to be arranged between the insu-'latcd conductors and said casing,the end of the shieldins'erted into thecasing being of prong formation and the outer end of' the shieldcomprising a split tube having an outwardly extending body adapted toengage the end portion of the casing to firmly retain the conductorswithin the casing and to insulate the same therefrom, and said outwardlyextendin body having a tapered Wall whereby said slueld may be wedged inposition.

2. The combination with insulated electric conductors arranged in anouter metallic cas ing, of a shield-composed of insulating mate-'rialadapted to be arranged between the insulated conductors, and saidcasing, the end of the shield inserted into the casing being of prongformation and the outer end of the shield comprising a split tube havingan outwardly extending body adapted to engage the end: ortion ofv thecasing'to firmly retain the :con uctors within-the casing and toinsulate the same theref r m said outwardly extendsaid shield may prongend of said body including an outward- I 1y pressed member adapted toengage the bore of said casing to aid in retaining the shield againstdisplacement.

3. The combination with insulated electric conductors arranged in anouter metallic casing. of a shield composed ofinsulating' materialadapted to be arranged between the insulated conductors and-said casing,the end of the shield inserted into the casing being of prong formationand the outer end of the shield comprising a split tube havinganoutwardly extending body adapted to engage the end portion ofthecasing to firmly retain, the conductors within the casing and toinsulate the same therefrom, said outwardly extending body having atapered Wall Whereby saidsliield may be wedged in position, and saidshield including anoutwardly projecting collar forming a finger pieceand insulating member.

it. The combination with insulated electric conductors arranged in anouter metallic casing, of a shield composed of insulating materialadapted to be arranged between the insuconductors within the casing andto insulate the same therefrom, and the side edge walls of the prong endof said shield being curved and tapered from the pointed end thereof tosaid outwardly extending body.

5. An insulator shield for conductors of the class specified comprisinga split tubular body, the walls of the split portion being beveled andcurved at one end of ,said body to, form a prong end portion and theother end of said body having'a radially and outwardly projectingmember, one wall of which is tapered in the direction of the prong endof the bod 6. An insulator shield for conductors of the class specifiedcomprising a split tubular body, the walls of the split portion beingbev-- eled and curved at one end of said body to form a prong endportion and the other end of said'body having aradially and outwardlyprojecting member, one wall of which is tapered in the direction of theprong end of the body, and the last named end of the body hav: ing acollar arranged outwardly of said memer. I

7. An insulator shield for conductors of the class specified comprisinga split tubular body,the walls of the split portion being beveled andcurved at one end of said body to form a prong end portion and the otherend of said body having a radially and outwardly projecting member, onewall of which is tapered in the direction of the prong end of the body,the last named end of the body having a collar arranged outwardly ofsaid member, and another radially and outwardly 5 pressed memberarranged in'said body intermediate the pointed end of said body and thefirst named member.

8. An insulator shield for armored conductors of the class specified,comprising a split tubular body of insulating material, one

end portion of which is adapted to be inserted in the armor and arrangedbetween it and the conductors, the outer end portion of said shieldhaving a radially projecting annular member, the diameter of said memberbeing substantially equal to the outside diameter of said armor, andsaid radially projecting member being arc-shaped in cross sectionalform.

9. An insulator shield for conductors of the class specified comprisinga split tubular body of insulating material, said body having a radiallyand outwardly extending member arranged inwardly of one end thereof, andone wall of said member being tapered in the di- 5 rcction of the otherend of'said body.

10. An insulator shield for conductors of the class specified comprisinga split tubular body of insulating material, said body having a radiallyand outwardly extending member arranged inwardly of one end thereof,'one

wall of said member being tapered in the direction of the other-end ofsaid body. and the second named end of said body being of prongformation.

In testimony that we claim the foregoing as our invention we have signedour names this 18th day of March, 1929.

EDWIN J. SCHNEIDER. MERRITT B. BRADT.

